Apparatus for transferring substrates

ABSTRACT

An apparatus for transferring substrates includes a carrier to which substrates are loaded, an upper transfer unit transferring the carrier horizontally by applying thrust to the carrier, a lower transfer unit maintaining the lower body of the carrier at the horizontal in a non-contact status, a magnetic levitation module levitating the carrier magnetically, and a lower damper unit maintaining the lower center of gravity of the carrier levitated by the magnetic levitation module.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of application Ser. No. 12/155,005filed May 28, 2008 now U.S. Pat. No. 7,954,434, now allowed, whichclaims priority to Korean Patent Application No. 10-2007-0051828, filedMay 29, 2007, each of which are incorporated by reference in theirentirety for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for transferringsubstrates.

2. Description of the Related Art

Manufacturing semiconductor or flat panel displays such as liquidcrystal displays and plasma displays requires a series of highlysophisticated processes.

Loading and unloading of wafers or substrates is be done to carry outeach individual process. A method for transferring substrates into eachprocess chamber by using a vertically moving carrier is utilized for theabove loading and unloading.

FIG. 1 illustrates the structure of a conventional apparatus fortransferring substrates.

As illustrated in FIG. 1, a carrier 13 comprises a loading unit 13Cmounting substrates, an upper carrier bar 13A located inside a carrierguide 11A attached to an upper moving path, and a lower carrier bar 13Bbeing in contact with a roller and driven for horizontal transfer by themovement of the roller.

The carrier 13 as above is transferred horizontally within a processchamber 10 or between chambers by an apparatus for transferringsubstrates comprising a upper transfer unit 11 and a lower transfer unit12.

A conventional apparatus for transferring substrates has a problem thata lower carrier bar 13B attached to the roller of a lower transfer unit12 is often displaced from the roller. Such a problem decreases yield,thereby reducing productivity.

In particular, since substrates are transferred being glued to arotating roller, large friction force is generated and adverse effectdue to particles may arise.

SUMMARY OF THE INVENTION

An aspect of this document is to provide an apparatus of non-contacttype for transferring substrates, which can provide horizontal transferof the upper and lower body of a carrier after magnetic levitationthereof.

In an aspect, an apparatus for transferring substrates comprises acarrier to which substrates are loaded, an upper transfer unittransferring the carrier horizontally by applying thrust to the carrier,a lower transfer unit maintaining the lower body of the carrier at thehorizontal in a non-contact status, a magnetic levitation modulelevitating the carrier magnetically, and a lower damper unit maintainingthe lower center of gravity of the carrier levitated by the magneticlevitation module.

In another aspect, an apparatus for transferring substrates comprises acarrier to which substrates are loaded, an upper transfer unittransferring the carrier horizontally by applying thrust to the carrier,a lower transfer unit maintaining the lower body of the carrier at thehorizontal in a non-contact status, a magnetic levitation modulelevitating the carrier magnetically, and an upper damper unitmaintaining the upper center of gravity of the carrier levitated by themagnetic levitation module.

In a yet another aspect, an apparatus for transferring substratescomprises a carrier to which substrates are loaded, an upper transferunit transferring the carrier horizontally by applying thrust to thecarrier, a lower transfer unit maintaining the lower body of the carrierat the horizontal in a non-contact status, a magnetic levitation modulelevitating the upper body of the carrier magnetically, a lower damperunit maintaining the lower center of gravity of the carrier levitated bythe magnetic levitation module and an upper damper unit maintaining theupper center of gravity of the carrier levitated by the magneticlevitation module.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompany drawings, which are included to provide a furtherunderstanding of the invention and are incorporated on and constitute apart of this specification illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

FIG. 1 illustrates the cross section of a conventional apparatus fortransferring substrates;

FIG. 2 illustrates an apparatus for transferring substrates according toa first embodiment of the invention;

FIG. 3 illustrates a squint view of an apparatus for transferringsubstrates illustrated in FIG. 2;

FIG. 4 illustrates a front view of an apparatus for transferringsubstrates illustrated in FIG. 2;

FIG. 5 illustrates the structure where a lower damper unit illustratedin FIG. 2 is installed;

FIG. 6 illustrates an apparatus for transferring substrates according toa second embodiment of the invention;

FIG. 7 illustrates a squint view of an apparatus for transferringsubstrates illustrated in FIG. 6;

FIG. 8 illustrates a front view of an apparatus for transferringsubstrates illustrated in FIG. 6;

FIG. 9 illustrates an apparatus for transferring substrates according toa third embodiment of the invention;

FIG. 10 illustrates a squint view of an apparatus for transferringsubstrates illustrated in FIG. 9; and

FIG. 11 illustrates a front view of an apparatus for transferringsubstrates illustrated in FIG. 9.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Reference will now be made in detail embodiments of the inventionexamples of which are illustrated in the accompanying drawings.

FIG. 2 illustrates a cross section of an apparatus for transferringsubstrates according to a first embodiment of the invention. FIG. 3illustrates a squint view of an apparatus for transferring substratesillustrated in FIG. 2 and FIG. 4 illustrates a front view of anapparatus for transferring substrates illustrated in FIG. 2.

With reference to FIGS. 2 through 4, an apparatus for transferringsubstrates according to the first embodiment of the invention includes acarrier 120 to which substrates 110 are loaded; an upper transfer unit130 transferring the carrier 120 horizontally, a lower transfer unit 150maintaining the lower body of the carrier 120 at the horizontal in anon-contact status, a magnetic levitation module 140 levitating thecarrier 120 magnetically, and a lower damper unit installed to the lowerbody of the carrier 120.

The carrier 120 includes a body 122 to which a substrate 110 is mountedvertically and a head 124 having an inclination part 124A whose diameterenlarges along upward direction at the upper part of the body 122.

Inside the body 122, a loading unit 122A for loading a substrate 110 isprepared.

Since the above carrier 120 transfers a substrate 110 by mounting thesubstrate 110 vertically as shown in the figure, it is effective fromthe standpoint of space utilization and substrate drooping.

The substrate 110 maybe for manufacturing flat panel displays as well asliquid crystal displays, which may further includes the case of asemiconductor wafer.

The upper transfer unit 130 applies thrust to the carrier 120 by usingtiming belt, rack and pinion gear, roller, ball screw, or linear motor,thereby transferring the carrier 120 horizontally.

In particular, when a linear motor is employed, the carrier 120 can betransferred horizontally in a non-contact way.

A linear motor includes a stator and an agitator. A stator may be formedby a plurality of coil arranged along moving direction of an agitator.The agitator may be formed by magnets arranged to stir the coil of thestator.

Accordingly, when current flows through the stator coil, the linearmotor generates Lorenz force against the stator to move the agitator ina direction vertical to the ground. Due to the force, the agitator ismoved horizontally relative to the agitator and the carrier 120 coupledto the agitator is moved horizontally.

The magnetic levitation module 140 is so structured that levitationforce is generated by push force established between magnets.

As illustrated in FIGS. 2 and 3, the magnetic levitation module 140includes a first permanent magnet 142 formed at the head 124 of thecarrier 120 along the inclination part 124A, a second permanent magnet144 installed opposite to the first permanent magnet 142, and asupporting member 146 supporting the second permanent magnet 144.

Since the second permanent magnet 144 has actually the same polarity asthe first permanent magnet 142, push force is generated pushing thesecond permanent magnet 144 from the first permanent magnet 142.

The second permanent magnet 144 follows the size and shape of the firstpermanent magnet 142. The first permanent magnet 142 is either a singlelong magnet formed at the head 124 of the carrier 120 along theinclination part 124A or a set of magnets of a fixed size installedalong the inclination part 124A.

Different from the moving mechanism of the magnetic levitation module140 utilizing push force of a magnet, the lower transfer unit 150maintains the carrier 120 at the horizontal being levitated magneticallyfrom the ground by using push force of a magnet.

The above lower transfer unit 150 includes a third permanent magnet 152installed in the lower body of the carrier 120 and a fourth permanentmagnet 154 installed opposite to the third permanent magnet 152 and withpolarity different from the third permanent magnet 152.

Since the fourth permanent magnet 154 is fixed to the bottom surfacewithin a process chamber 100, the carrier 120 is maintained at thehorizontal in a non-contact status by pull force exercised between thefourth permanent magnet 154 and the third permanent magnet 152.

At this time, the magnetic levitation module 140 and the lower transferunit 150 require control of levitation force according to the weight ofthe carrier 120.

Recently, as the size of a substrate increases, the size of the carrier120 also increases. Accordingly, the levitation force to levitate thecarrier 120 should be increased and since the weight of the carrier 120varies according to individual equipment, control of levitation force byadjusting levitation gap is required.

For example, if push force exercised by the magnetic levitation module140 is strong relative to the weight of the carrier 120 whereas pullforce exercised by the lower transfer unit 150 is weak relative to thepush force, the lower body of the carrier 120 levitated magnetically maynot be kept horizontal in a non-contact status, being inclined in onedirection or displaced from the normal position.

The lower damper unit 160 is intended for controlling the levitation gapof the carrier 120. The lower damper unit 160 includes comprising alower housing 162 encompassing both parts of the lower body of thecarrier 120 and multiple dampers 164 installed inside the lower housing162.

The lower housing 162 is installed to the front and the rear of thecarrier 120, covering both sides of the carrier 120 by assembly.Alternatively, the lower housing 162 is installed in the form of a cap,covering both sides of the lower body of the carrier 120.

The lower housing 162 is fixed in a process chamber 100 and hooks 162Aare installed at the upper and lower part thereof.

Hooks restrict levitation force of the carrier 120 levitatedmagnetically, thereby preventing the carrier 120 from being inclined inone direction due to magnetic force (push and pull force) exercisedthrough the magnetic levitation module 140 and the lower transfer unit150.

Multiple dampers 164 are prepared inside the lower housing 162 andsurfaces facing opposite to each other come into contact with thecarrier 120 and the inner surface of the lower housing 162,respectively.

To explain more specifically, multiple dampers 164 may include a firstdamper 164B installed between the side of the carrier 120 and the lowerhousing 162; and a second damper 164A installed between the hook 162A ofthe lower housing 162 and the carrier 120.

At this time, in one side of the carrier 120 with which multiple dampers164 come into contact, grooves (not shown) into which part of thedampers 164 are inserted may be formed.

For example, multiple dampers 164 may be a roller.

In this case, the rotating axis of multiple dampers 164 is installeddifferently according to the installation position.

In other words, with reference to FIG. 5, for the case of a first damper164B installed between the side of the carrier 120 and the lower housing162, multiple dampers are installed with an axis orthogonal to thedirection of the carrier 120 (A axis) as the rotating axis. For the caseof a second damper 164A installed between the hooks 162A of the lowerhousing 162 and the carrier 120, multiple dampers are installed with anaxis orthogonal to the direction of levitation of the carrier 120 (Baxis) as the rotating axis.

Accordingly, multiple dampers 164 keep the lower center of gravity ofthe magnetically levitated carrier 120 from being displaced from anormal position, minimize collision between the carrier 120 and thelower housing 162, and prevent generation of particles by minimizingfriction between the carrier 120 and the lower housing 162.

Meanwhile, for the lower damper unit 160, magnetic force exercised tothe upper and lower part of the carrier 120 varies according to externalenvironment or the weight of the carrier 120. Accordingly, levitationforce of the carrier 120 can be varied; for this case, the lower housing162 can adjust levitation force of the carrier 120 through multipledampers 164.

That is to say, the lower damper unit 160 can maintain levitation gapwhere the carrier 120 is levitated by interaction between multipledampers 164. In particular, control of the levitation gap is madepossible by restricting levitation force of the carrier 120 by utilizingthe hooks 162A of the lower housing 162.

FIG. 6 illustrates a cross section of an apparatus for transferringsubstrates according to a second embodiment of the invention. FIG. 7illustrates a squint view of the apparatus for transferring substratesillustrated in FIG. 6 and FIG. 8 is a front view of the apparatus fortransferring substrates illustrated in FIG. 6.

An apparatus for transferring substrates according to a secondembodiment of the invention transfers the carrier 220 horizontally bylevitating the carrier 220 by using push force generated betweenmagnets.

At this time, push force generating levitation force causes lateralforce which inclines a subject in one direction as well as thelevitation force. Such lateral force becomes large as the levitationforce enlarges.

Accordingly, an apparatus for transferring substrates according to thesecond embodiment of the invention reduces inclination phenomenagenerated by lateral force by applying a damper at the upper part of thecarrier 220, thereby providing a stable carrier conveyance system.

Referring to FIG. 6, an apparatus for transferring substrates accordingto the second embodiment of the invention includes a carrier 220 towhich substrates 210 are loaded, an upper transfer unit 230 transferringthe carrier 220 horizontally by applying thrust to the carrier 220, alower transfer unit 250 maintaining the lower body of the carrier 220 atthe horizontal in a non-contact status, a magnetic levitation module 240levitating the carrier 220 magnetically, and an upper damper unit 270maintaining the upper center of gravity of the carrier 220 levitated bythe magnetic levitation module 240.

Hereinafter, description of components also used in an apparatus fortransferring substrates according to the first embodiment is omitted;only components not found in the first embodiment are described.

A magnetic levitation module 240 of an apparatus for transferringsubstrates according to the second embodiment of the invention includestwo permanent magnets 242, 244 and a supporting member 246 forgenerating levitation force by push force between magnets.

As illustrated in FIGS. 6 and 7, a first permanent magnet is installedat the head 224 of the carrier 220 along the inclination part 224A. Thefirst permanent magnet 242 is either a single long magnet formed alongthe inclination part 224A or a set of magnets of a fixed size installedalong the inclination part 224A.

Since the second permanent magnet 244 is installed opposite to the firstpermanent magnet 242 and has actually the same polarity as the firstpermanent magnet 242, push force is generated between the firstpermanent magnet 242 and the second permanent magnet 244.

The supporting member 246 is installed according to the head 224 shapeof the carrier 220 and is located at the lower body of the inclinationpart 224A, supporting the second permanent magnet 244 installed oppositeto the first permanent magnet 242.

The supporting member 246 has an inclination in such a way that theupper surface of the supporting member 246 facing the inclination part224A correspond to the inclination part 224A and the side surface of thesupporting member 246 facing the carrier 220 has a groove 246A.

The upper damper unit 270 is intended for preventing the carrier 220levitated by the magnetic levitation module 240 from being inclinedtowards both sides by lateral force, the upper damper unit 270 includingmultiple dampers 272 installed along horizontal direction of the carrier220.

To be more specific, multiple dampers 272 are installed between thesupporting member 246 of the magnetic levitation module 240 and thecarrier 220.

Therefore, surfaces of multiple dampers 272 facing each other makecontact with the carrier 220 and the magnetic levitation module 240respectively, maintaining the upper center of gravity of the carrier 220levitated by the magnetic levitation module 240 against lateral force.Accordingly, since the center of gravity of the carrier 220 is kept at aright position not inclined towards both sides, generation of particlesdue to friction is prevented.

One of the surfaces of the carrier 220 with which multiple dampers 272make contact may carry a groove (not shown) along which part of thedampers 272 can be inserted.

Each of the dampers 272 can be realized by a roller. As illustrated inthe figure, a roller can be installed in a pair at both surfaces of thecarrier 220 or each of the dampers 272 can be realized by a rollerpenetrating the carrier 220.

In this case, the roller is installed in such a way that the roller isrotated around an axis orthogonal to the direction of levitation of thecarrier 220, thus reducing friction between the magnetic levitationmodule 240 and the carrier 220.

Moreover, since multiple dampers 272 make contact with the carrier 220while being inserted in the groove 246A of the supporting member 246,displacement of multiple dampers 272 due to lateral force can beprevented.

FIG. 9 illustrates a cross section of an apparatus for transferringsubstrates according to a third embodiment of the invention. FIG. 10illustrates a squint view of an apparatus for transferring substratesillustrated in FIG. 9 and FIG. 11 illustrates a front view of anapparatus for transferring substrates illustrated in FIG. 9.

The structure of an apparatus for transferring substrates according tothe third embodiment of the invention is a combination of the structureof an apparatus for transferring apparatus according to the firstembodiment and the structure of an apparatus for transferring substratesaccording to the second embodiment, having both a lower damper unit 360and an upper damper unit 370 at the lower and upper body of a carrier320.

Referring to FIG. 9 to be more specific, an apparatus for transferringsubstrates according to the third embodiment of the invention includes acarrier 320 to which substrates 310 are loaded; an upper transfer unit330 transferring the carrier 320 horizontally by applying thrust to thecarrier 320, a lower transfer unit 350 maintaining the lower body of thecarrier 320 at the horizontal in a non-contact status, a magneticlevitation module 340 levitating the carrier 320 magnetically, a lowerdamper unit 360 maintaining the lower center of gravity of the carrier320 levitated by the magnetic levitation module 340, and an upper damperunit 370 for maintaining the upper center of gravity of the carrier 320levitated by the magnetic levitation module 340.

The carrier 320 includes a body 322 to which a substrate 310 is mountedvertically and a head 324 having an inclination part 324A whose diameterenlarges along upward direction at the upper part of the body 322.

Inside the body 322, a loading unit 322A for loading a substrate 310 isprepared.

Since the above carrier 320 transfers a substrate 310 by mounting thesubstrate 310 vertically as shown in the figure, it is effective fromthe standpoint of space utilization and substrate drooping.

The substrate 310 maybe for manufacturing flat panel displays as well asliquid crystal displays, which may further include the case of asemiconductor wafer.

The upper transfer unit 330 applies thrust to the carrier 320 by usingtiming belt, rack and pinion gear, roller, ball screw, or linear motor,thereby transferring the carrier 320 horizontally.

In particular, when a linear motor is employed, the carrier 320 can betransferred horizontally in a non-contact way.

As illustrated in FIGS. 9 and 10, the magnetic levitation module 340 isso structured that levitation force is generated by push forceestablished between magnets.

So to speak, the magnetic levitation module 340 includes a firstpermanent magnet 342 formed at the head 324 of the carrier 320 along theinclination part 324A, a second permanent magnet 344 installed oppositeto the first permanent magnet 342, and a supporting member 346supporting the second permanent magnet 344.

Since the second permanent magnet 344 has actually the same polarity asthe first permanent magnet 342, push force is generated pushing thesecond permanent magnet 344 from the first permanent magnet 342.

The second permanent magnet 344 follows the size and shape of the firstpermanent magnet 342. The first permanent magnet 342 is either a singlelong magnet formed at the head 324 of the carrier 320 along theinclination part 324A or a set of magnets of a fixed size installedalong the inclination part 324A.

A supporting member 346 is installed at the lower body of the head 324separated from the inclination part 324A. The upper surface of thesupporting member 346 facing the inclination part 324A is inclinedparallel to the inclination part 324A and the side surface of thesupporting member 346 facing the carrier 320 has a groove 346A.

The lower transfer unit 350 maintains the carrier 320 at the horizontalbeing levitated magnetically from the ground by using push force betweenmagnets.

The above lower transfer unit 350 includes a third permanent magnet 352installed in the lower body of the carrier 320 and a fourth permanentmagnet 354 installed opposite to the third permanent magnet 352 and havepolarity different from the third permanent magnet 352.

Since the fourth permanent magnet 354 is fixed to the bottom surfacewithin a process chamber 300, the carrier 320 is maintained at thehorizontal in a non-contact status by pull force exercised between thefourth permanent magnet 354 and the third permanent magnet 352.

At this time, the magnetic levitation module 340 and the lower transferunit 350 require control of levitation force by adjusting levitation gapaccording to the weight of the carrier 320.

For example, if push force exercised by the magnetic levitation module340 is strong relative to with the weight of the carrier 320 whereaspull force exercised by the lower transfer unit 350 is weak relative tothe push force, the lower body of the carrier 320 levitated magneticallymay not be kept at the horizontal in a non-contact status, beinginclined in one direction or displaced from the normal position.

The lower damper unit 360 is intended for controlling levitation gap ofthe carrier 320, including a lower housing 362 encompassing both partsof the lower body of the carrier 320, multiple dampers 364 installedinside the lower housing 362, and hooks 362A installed at the upper andlower part of the lower housing 362.

At this time, hooks 362A restrict levitation force of the carrier 320levitated magnetically, thereby preventing the carrier 320 from beinginclined in one direction due to magnetic force (push and pull force)exercised through the magnetic levitation module 340 and the lowertransfer unit 350.

Multiple lower dampers 364 can be installed in the form of a roller andcan include a first lower damper 364A installed between the hook 362Aand the carrier 320 to reduce friction against the carrier 320 insidethe lower housing 362 and a second lower damper 364B installed betweenthe side surface of the carrier 320 and the lower housing 362.

Since installation structure of multiple lower dampers 362 andinteraction of the multiple lower dampers 362 with the lower housing arethe same as described in the first embodiment, detailed descriptions areomitted.

The lower damper unit 360 structured as above prevents the carrier 320from being inclined in one direction or displaced by maintaining thelower center of gravity of the carrier 320 levitated magnetically andprevents generation of particles by minimizing friction between thecarrier 320 and the lower housing 362.

The upper damper unit 370 is intended for preventing the carrier 320levitated by the magnetic levitation module 340 and the lower transferunit 350 from being inclined towards both sides by lateral force, theupper damper unit 270 including multiple upper dampers 372 installedalong horizontal direction of the carrier 320.

The carrier 320 obtains stable levitation force while maintaininglevitation gap by utilizing the lower transfer unit 350 and the lowerdamper unit 360. As levitation force becomes large, however, lateralforce is bound to be generated, by which the carrier 320 gets inclinedto both sides.

Accordingly, the upper dampers 372 of the damper unit 370 are locatedbetween the supporting member 346 of the magnetic levitation module 340and surfaces of the upper dampers 372 facing each other are installed insuch a way to make contact with the carrier 320 and the magneticlevitation module 340, respectively.

At this time, a groove (not shown) into which part of the upper dampers372 are inserted can be formed in the contacting surface of the carrier320 with which multiple upper dampers 372 make contact.

Based on the structure above, since the upper damper unit 370 maintainsthe upper center of gravity of the carrier 320 (which has levitatedwhile preserving some levitation gap) at the center between both sidesagainst lateral force in order for the carrier 320 not to collideagainst the sides, generation of particles due to friction can beprevented.

Therefore, an apparatus for transferring substrates according to thethird embodiment of the invention transfers the carrier 320 in anon-contact way by levitating the carrier 320 magnetically by usingmagnetic force through the magnetic levitation module 340 and the lowertransfer unit 350 and maintains levitation gap by using the lower damperunit 360 of the carrier 320 to secure stable levitation force. Moreover,the apparatus prevents generation of particles due to friction betweenthe carrier 320 and the magnetic levitation module 340 by maintainingthe upper center of gravity of the carrier 320 against lateral forcegenerated together with levitation force.

In other words, a stable transfer system is provided by eliminating allthe causes of generation of particles.

As described in detail above, an apparatus for transferring substratesaccording to one embodiment of the invention, by levitating magneticallythe upper and lower part of a carrier holding a substrate vertically byusing push force between magnets, brings an effect of transferring thesubstrate horizontally in a not-contact way. Accordingly, since frictionforce during transfer of substrates becomes minimized, adverse effectdue to particles can be avoided.

Also, as the upper and lower center of gravity of a carrier aremaintained by applying dampers to the upper and lower part of thecarrier levitated magnetically, one can obtain an effect of preventinggeneration of particles due to friction and providing a stable transfersystem.

Further, by maintaining a constant levitation gap of a carrier, one canobtain an effect of adjusting levitation force that can be variedaccording to the weight of the carrier.

The foregoing embodiments and advantages are merely exemplary and arenot to be construed as limiting the present invention. The presentteaching can be readily applied to other types of apparatuses. Thedescription of the foregoing embodiments is intended to be illustrative,and not to limit the scope of the claims. Many alternatives,modifications, and variations will be apparent to those skilled in theart. In the claims, means-plus-function clauses are intended to coverthe structures described herein as performing the recited function andnot only structural equivalents but also equivalent structures.Moreover, unless the term “means” is explicitly recited in a limitationof the claims, such limitation is not intended to be interpreted under35 USC 112(6).

1. An apparatus for transferring substrates, comprising: a carrier towhich substrates are loaded; an upper transfer unit transferring thecarrier horizontally by applying thrust to the carrier; a lower transferunit maintaining the lower body of the carrier at the horizontal in anon-contact status; a magnetic levitation module levitating the carriermagnetically; and an upper damper unit maintaining the upper center ofgravity of the carrier levitated by the magnetic levitation module andincluding multiple dampers, wherein the multiple dampers are installedin such a way that the carrier and the magnetic levitation modulerespectively make contact with surfaces of the multiple dampers oppositeto each other, and wherein the multiple dampers are a roller rotatingaround an axis having direction orthogonal to the direction along whichthe carrier is installed.
 2. The apparatus of claim 1, wherein thecarrier comprises, a body to which the substrate is mounted vertically;and a head having an inclination part whose diameter enlarges alongupward direction at upper part of the body.
 3. The apparatus of claim 2,wherein the magnetic levitation module comprises, a first permanentmagnet installed at the inclination part of the head; a second permanentmagnet installed opposite to the first permanent magnet, having actuallythe same polarity as the first permanent magnet; and a supporting membersupporting the second permanent magnet.
 4. The apparatus of claim 3,wherein the supporting member contacting the multiple dampers has agroove into which the multiple dampers can be inserted.
 5. The apparatusof claim 1, wherein the upper transfer unit is a linear motor.
 6. Theapparatus of claim 1, wherein the lower transfer unit comprises, a thirdpermanent magnet installed at the lower part of the carrier; and afourth permanent magnet installed opposite to the third permanentmagnet, having different polarity from the third permanent magnet. 7.The apparatus of claim 1, wherein the multiple dampers are installed toboth sides of the carrier.
 8. The apparatus of claim 1, wherein themultiple dampers are installed by penetrating the carrier.
 9. Anapparatus for transferring substrates, comprising: a carrier to whichsubstrates are loaded; an upper transfer unit transferring the carrierhorizontally by applying thrust to the carrier; a lower transfer unitmaintaining the lower body of the carrier at the horizontal in anon-contact status; a magnetic levitation module levitating the upperbody of the carrier magnetically; a lower damper unit maintaining thelower center of gravity of the carrier levitated by the magneticlevitation module; and an upper damper unit maintaining the upper centerof gravity of the carrier levitated by the magnetic levitation moduleand including multiple dampers, wherein the multiple dampers areinstalled in such a way that the carrier and the magnetic levitationmodule respectively make contact with surfaces of the multiple dampersopposite to each other, and wherein the multiple damper is a rollerrotating around an axis having direction orthogonal to the directionalong which the carrier is installed.